One of the major environmental problems confronting the United States and other countries is pollution caused by the emission of gaseous and other pollutants in the exhaust gases from internal combustion engines such as automobiles. This problem is especially acute in areas having a high concentration of internal combustion engines, such as in major metropolitan areas.
It is known that at least three gaseous constituents or pollutants, which contribute to pollution due to engine exhaust are nitrogen oxides (NOx), carbon monoxide (CO), and unburned or incompletely burned hydrocarbons (i.e., hydrocarbon components originally present in the gasoline fuel which are not fully converted to carbon monoxide or dioxide and water during combustion in the automobile engine).
As a result of pollution caused by the internal combustion engine, laws and regulations have been established to mitigate pollution by reducing gaseous constituents or pollutants by controlling the composition of gasoline fuels. Such specially formulated, low emission gasolines are often referred to as reformulated gasolines. One of the requirements of these gasoline regulations is blending, in certain geographic areas, certain additives, such as oxygen-containing hydrocarbons, or oxygenates, into the fuel.
Oxygenated gasoline is a mixture of conventional hydrocarbon-based gasoline and one or more oxygenates. Oxygenates are combustible liquids which are made up of carbon, hydrogen and oxygen. Generally, the current oxygenates used in reformulated gasolines belong to one of two classes of organic molecules: alcohols and ethers.
There are concerns associated with the use of oxygenates in fuel. Therefore, cleaner burning gasoline without oxygenates are a possibility.